1.6.13 Shape Similarity

INPUT OUTPUT

Input Description:
Two polygonal shapes, P_1 and P_2.

Problem:
How similar are P_1 and P_2?

Excerpt from
The Algorithm Design Manual:
Shape similarity is a problem that underlies much of pattern
recognition.
Consider a system for optical character recognition (OCR).
We have a known library of shape models representing letters and the unknown
shapes we obtain by scanning a page.
We seek to identify an unknown shape by matching it to
the most similar shape model.

The problem of shape similarity is inherently ill-defined,
because what ``similar'' means is application dependent.
Thus no single algorithmic approach can solve all
shape matching problems.
Whichever method you select, expect to spend a large chunk of time
tweaking it so as to achieve maximum performance.
Don't kid yourself -- this is a difficult problem.